Search results for "BERYLLIUM"
showing 10 items of 65 documents
Efficient and robust photo-ionization loading of beryllium ions
2017
We demonstrate the efficient generation of Be$^+$ ions with a 60 ns and 150 nJ laser pulse near 235 nm for two-step photo-ionization, proven by subsequent counting the number of ions loaded into a linear Paul trap. The bandwidth and power of the laser pulse are chosen in such a way that a first, resonant step fully saturates the entire velocity distribution of beryllium atoms effusing from a thermal oven. The second excitation step is driven by the same light field causing efficient non-resonant ionization. Our ion-loading scheme is more than 15 times more efficient as compared to former pathways using two-photon continuous wave laser excitation.
Tritium distribution and chemical forms in the irradiated beryllium pebbles before and after thermoannealing
2011
Abstract Beryllium pebbles are foreseen as a neutron multiplier in the tritium breeding blanket of the future fusion devices. Tritium inventory in the beryllium as a result of neutron-induced transmutations is a significant safety and technological issue for the operation of the breeding blanket. In this study, beryllium pebbles from 3 different irradiation experiments: BERYLLIUM, EXOTIC 8/3-13 and PBA, performed at High Flux Reactor HFR have been investigated. The distribution of tritium in the bulk of the pebbles and the abundance ratios of chemical forms of tritium T 0 , T + and T 2 have been analysed before and after the different thermo-annealing experiments. In order to determine the …
Activity monitoring of a gaseous tritium source by beta induced X-ray spectrometry
2013
Abstract For monitoring and control of gaseous tritium sources in fuel circulation systems of fusion reactors beta induced X-ray spectrometry (BIXS) seems to be an applicable method. The characteristics of a BIXS monitoring setup built at TLK were examined. A low-noise silicon drift detector (SDD) was used together with two thin beryllium windows evaporated with gold films of 100 nm for efficient X-ray production. The measured X-ray intensity was proportional to the tritium partial pressure and the average detection efficiency was evaluated as 32.6 × 10−8 cps/Bq. A tritium memory effect was revealed. From the results it was concluded that such a monitoring system would be a useful complemen…
Experimental tests and thermo-mechanical analyses on the HEXCALIBER mock-up
2008
Abstract Within the framework of the R&D activities promoted by European Fusion Development Agreement on the helium-cooled pebble bed test blanket module to be irradiated in ITER, ENEA Brasimone and the Department of Nuclear Engineering of the University of Palermo performed intense research activities on the modelling of the thermo-mechanical behaviour of both beryllium and lithiated ceramics pebble beds, which are envisaged to be used, respectively, as neutron multiplier and tritium breeder. In particular, at the DIN a thermo mechanical constitutive model was developed for both lithiated ceramics and beryllium pebble beds and it was successfully implemented on a commercial finite element …
On the theoretical–numerical study of the HEXCALIBER mock-up thermo-mechanical behaviour
2010
Abstract Within the framework of the R&D activities promoted by European Fusion Development Agreement on the Helium-Cooled Pebble Bed Test Blanket Module to be irradiated in ITER, ENEA Brasimone and the Department of Nuclear Engineering of the University of Palermo (DIN) performed intense research activities on the modelling of the thermo-mechanical behaviour of both beryllium and lithiated ceramics pebble beds, that are envisaged to be used, respectively, as neutron multiplier and tritium breeder. In particular, the DIN developed a thermo-mechanical constitutive model for these pebble beds to be validated against the HEXCALIBER mock-up test campaign, carried out at the ENEA HE-FUS3 facilit…
CONCENTRATION MEASUREMENTS OF 7Be AT GROUND LEVEL AIR AT PALERMO, ITALY- COMPARISON WITH SOLAR ACTIVITY OVER A PERIOD OF 21 YEARS
2003
Air activity concentrations of (7)Be in Palermo determined for the period January 1995-December 2002 by gamma-ray spectrometric analysis of particulate samples collected on paper filter by a high-volume sampler (approximately 900 m(3) h(-1)) are reported. The temporal behaviour of (7)Be concentration presents the same characteristics already observed in the measurements carried out over the previous 13-year (1982-1994) investigated period. The mean value of 5.06 mBq m(-3) obtained from the analysis of the 4636 particulate samples collected from 1982 to 2002 can be considered a representative value of (7)Be air concentration at ground level in our geographical zone. The comparison of long-te…
Magnetic field effects on tritium release from neutron-irradiated beryllium pebbles
2007
The effects of temperature, magnetic field (MF), and ionizing radiation on the release of tritium from the Be pebbles irradiated in the BERYLLIUM experiment in 1994 in Petten, The Netherlands (irradiation neutron fluence 1.24×10 25 m -2 , irradiation temperature 780 K, and 3 H content 7 appm) were investigated in this study. Simultaneous action of these factors corresponds to the real operating conditions of the blanket of a fusion reactor. The total amount of tritium in a separate pebble, the chemical forms of localized tritium (T 0 , T 2 , and T + ), and the tritium distribution in the pebble volume were determined by a lyomethod (dissolution). Thermoannealing experiments were performed a…
Tritium release behavior of beryllium pebbles after neutron irradiation between 523 and 823K
2013
Abstract Post-irradiation tritium release from the Pebble Bed Assembly (PBA) neutron-irradiated beryllium (Be) pebbles (∅ ≈ 1 mm; the total tritium inventory 2–4 GBq/g) was investigated on annealing in He + 0.1% H 2 . Temperature ramps of 2.3 K/min followed by annealing for 1 h at 1310–1320 K resulted in complete detritiation of the PBA Be pebbles. The tritium burst release occurred after a time lag of 1–6.5 h during constant temperature anneals at 1089–1180 K, with the release time measured after reaching the annealing temperature. Tritium burst release was also observed to occur during cool down. Anneals at 1089 K for 8 h and at 1045 K for 23 h caused detritiation of the PBA Be pebbles by…
Tritium release from beryllium articles for use in fusion devices
2009
Abstract Results obtained on radiation and magnetic field (MF) effects on tritium release at annealing of the beryllium pebbles from the EXOTIC-8-3/13 irradiation are presented in this study and compared with those for other irradiated beryllium materials. Abundance ratios of chemical forms of tritium in the EXOTIC-8-3/13 beryllium pebbles were determined: T 2 – 65%, T 0 – 23%, T + – 12%. A complete detritiation of these pebbles was achieved at 1123 K for 240 min; MF of 2.35 T had no appreciable effect on the tritium release. At 991 K for 240 min, the degree of detritiation was 96.6% without MF; MF of 2.35 T decreased it to 86.7%. At 940 K for 47 min, the degree of detritiation was 60%, 5 M…
Tritium retention in plasma facing materials of JET ITER-Like-Wall retrieved from the vacuum vessel in 2012 (ILW1), 2014 (ILW2) and 2016 (ILW3)
2021
Abstract ITER-Like-Wall (ILW) project has been carried out at Joint European Torus (JET) to test plasma facing materials relevant to International Thermonuclear Experimental Reactor – ITER [1]. Limiters and an upper dump plate of the vacuum vessel are made of bulk beryllium tiles, whereas for the divertor bulk tungsten and tungsten-coated carbon fibre (CFC) composite tiles are used. During the shutdowns in ILW1 (2012), ILW2 (2014) and ILW3 (2016), selected beryllium tiles were removed from the vacuum vessel. In this study, tiles from three positions were analysed, and analysis results were compared regarding both the tile position in the vacuum vessel and differences in the exploitation con…